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Help soldering on a multi-layered board

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Hi all,

I was just wondering if I can pick your brains as to how to go about fixing a little problem I have with an RJ45 socket connector I am trying to resolder. I have recently purchase a second hand IBM x61 laptop off ebay and found that the LAN port does not work. So of course I opened it up to find the connector's joints on the mainboard PCB looking not so good and possibly like someone had tried soldering the connector previously without success. The laptops lan works fine using the docking station so I know from the schematics that everything is working up until the last IC, responsible for switching between the docking station and the onboard RJ45. So between that IC and the RJ45 socket there seems to be a problem. The PCB joints look terrible as you can see in the photos. They maybe a little worse than when I found them but not by much. Two of the pins in the fist photo seem to not have any pad to solder to. So the issue is that I cant seem to resolder the connector as is. The holes in the board dont seem to want to fill and i'm not sure being a multi layered board if there is a trick to this. Is this beyond repair? I would trace each pin back but being a laptop and a small one at that seems to make things rather difficult. Any help would be most appreciated.

Due to the image limit, I have put more images/schematics etc on http://fullof.info/x61

It looks like it needs a good cleaning. Hit the area with some rubbing alcohol and a toothbrush to clean out all the dirt and funk. The joints that are there are bulging, which is a sign that there wasn't enough flux to properly wet or clean the metal underneath.

If it were me I'd clean it, use a flux pen and solder wick to pull out what's there (don't have to get it all, just most), clean again, flux again, and resolder.

Hope that helps. :)

And if you find that re-soldering doesn't work then you need to trace the pin back to something you can solder to.  Run a thin insulated wire between the ethernet pin and where it should connect to something else.

You may find this link useful



As a note. Docking station usually has its own integrated LAN card.

What I think is that connector was actually removed because of the extensive damage. Is it 100MBit or a GB card ?

I would clean that burned flux first. Cotton swabs and acetone would do.
It seems a capacitor or resistor was sheared off as well.

Clean the solder with solder wick or desoldering pump and apply fresh and good one. Also, board needs to be preheated - use hair dryer until it is hot to touch.
Once it is done, fix the connector with hot glue.


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